Aurora A-mediated pyruvate kinase M2 phosphorylation promotes biosynthesis with glycolytic metabolites and tumor cell cycle progression.

Cancer cells have distinctive demands for intermediates from glucose metabolism for biosynthesis and energy in different cell cycle phases. However, how cell cycle regulators and glycolytic enzymes coordinate to orchestrate the essential metabolic processes are still poorly characterized. Here, we report a novel interaction between the mitotic kinase, Aurora A, and the glycolytic enzyme, pyruvate kinase M2 (PKM2), in the interphase of the cell cycle. We found Aurora A-mediated phosphorylation of PKM2 at threonine 45. This phosphorylation significantly attenuated PKM2 enzymatic activity by reducing its tetramerization and also promoted glycolytic flux and the branching anabolic pathways. Replacing the endogenous PKM2 with a nonphosphorylated PKM2 T45A mutant inhibited glycolysis, glycolytic branching pathways, and tumor growth in both in vitro and in vivo models. Together, our study revealed a new protumor function of Aurora A through modulating a rate-limiting glycolytic enzyme, PKM2, mainly during the S phase of the cell cycle. Our findings also showed that although both Aurora A and Aurora B kinase phosphorylate PKM2 at the same residue, the spatial and temporal regulations of the specific kinase and PKM2 interaction are context dependent, indicating intricate interconnectivity between cell cycle and glycolytic regulators.

An analysis of clinical characteristics and prognosis of endometrioid ovarian cancer based on the SEER database and two centers in China.

PURPOSE: To assess the clinical characteristics and the risk factors related to the unfavorable prognosis of endometrioid ovarian carcinoma (EOVC) based on data from the Surveillance, Epidemiology, and End Results (SEER) database and two clinical centers in China. METHODS: Data were extracted from the SEER database and two clinical centers in China (2010 ~ 2021), 884 cases and 87 patients with EOVC were selected, respectively. Overall survival (OS) and progression-free survival (PFS) were compared among the different groups using Kaplan-Meier analysis. The Cox proportional-hazards model was used to identify independent prognostic factors related to EOVC. A nomogram was constructed based on the risk factors of the SEER database affecting prognosis and the discrimination and calibration of the nomogram were evaluated by C-index and calibration curves. RESULTS: The average age at diagnosis of patients with EOVC in the SEER database and two centers in China was 55.77 ± 12.40 years and 47.14 ± 11.50 years, 84.7% and 66.6% of them were diagnosed at FIGO stage I ~ II, respectively. In the SEER database, age over 70 years, advanced FIGO stage, tumor grade 3, only unilateral salpingo-oophorectomy were independent risk factors of unfavorable prognosis. In two clinical centers in China, 27.6% of EOVC patients were diagnosed with synchronous endometriosis. Advanced FIGO stage, HE4 > 179 pmol/L and bilateral ovarian involvement significantly correlated with poor OS and PFS in Kaplan-Meier analysis. Body mass index (BMI) < 19.34 kg/m2 was an independent risk factor relating to OS and PFS. Additionally, C-index of internal and external verification for the nomogram were 0.812 and 0.754 respectively, revealing good accuracy and clinical applicability. CONCLUSIONS: Most patients were diagnosed at early stage, low grade and had better prognosis. Asian/Pacific Islander and Chinese diagnosed with EOVC were more likely to be younger than whites and blacks. Age, tumor grade and FIGO stage (SEER database) and BMI (two centers) are independent prognostic factors. HE4 appears to be more valuable in prognostic assessment compared with CA125. The nomogram had good discrimination and calibration for predicting prognosis, providing a convenient and reliable tool for clinical decision-making for patients with EOVC.

Development of a one-plasmid system to replace the endogenous protein with point mutation for post-translational modification studies.

BACKGROUND: Post-translational modification (PTM) is one of the major regulatory mechanism for protein activities. To understand the function of PTMs, mutants that prevent or mimic the modification are frequently utilized. The endogenous proteins are usually depleted while the point mutations are expressed. A common strategy to accomplish these tasks includes two-steps: First, a cell line stably expressing shRNA for protein depletion is generated, then an RNAi-resistance construct is introduced to express mutant. However, these steps are time- and labor-consuming. More importantly, shRNA and mutant protein are frequently expressed in different cells at different time, which significantly disturbs the conclusions. METHODS: To overcome these technical problems, we developed a lentiviral based one-plasmid system that allowed concurrent expression of shRNA and mutant protein. The puromycin-resistant gene was inserted for the selection of stable-expression cells. RESULTS: Using this plasmid, we efficiently replaced the endogenous proteins with comparable levels of exogenous proteins for LDHB and PKM2, two glycolytic enzymes regulated by PTM in cancer cells. The system was also successfully exploited in evaluating the role of phosphorylation of LDHB serine 162 in multiple in vitro and in vivo assays. CONCLUSION: Thus, we have developed an efficient one-plasmid system to replace endogenous protein with point mutations for the functional study of PTM.

Mechanism of Metabolic Dysfunction-associated Steatotic Liver Disease: Important role of lipid metabolism.

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease, has a high global prevalence and can progress to metabolic dysfunction-associated steatohepatitis, cirrhosis, and hepatocellular carcinoma. The pathogenesis of MASLD is primarily driven by disturbances in hepatic lipid metabolism, involving six key processes: increased hepatic fatty acid uptake, enhanced fatty acid synthesis, reduced oxidative degradation of fatty acids, increased cholesterol uptake, elevated cholesterol synthesis, and increased bile acid synthesis. Consequently, maintaining hepatic lipid metabolic homeostasis is essential for effective MASLD management. Numerous novel molecules and Chinese proprietary medicines have demonstrated promising therapeutic potential in treating MASLD, primarily by inhibiting lipid synthesis and promoting lipid oxidation. In this review, we summarized recent research on MASLD, elucidated the molecular mechanisms by which lipid metabolism disorders contribute to MASLD pathogenesis, and discussed various lipid metabolism-targeted therapeutic approaches for MASLD.

Deep Learning-Based 3D Single-Cell Imaging Analysis Pipeline Enables Quantification of Cell-Cell Interaction Dynamics in the Tumor Microenvironment.

The three-dimensional (3D) tumor microenvironment (TME) comprises multiple interacting cell types that critically impact tumor pathology and therapeutic response. Efficient 3D imaging assays and analysis tools could facilitate profiling and quantifying distinctive cell-cell interaction dynamics in the TMEs of a wide spectrum of human cancers. Here, we developed a 3D live-cell imaging assay using confocal microscopy of patient-derived tumor organoids and a software tool, SiQ-3D (single-cell image quantifier for 3D), that optimizes deep learning (DL)-based 3D image segmentation, single-cell phenotype classification, and tracking to automatically acquire multidimensional dynamic data for different interacting cell types in the TME. An organoid model of tumor cells interacting with natural killer cells was used to demonstrate the effectiveness of the 3D imaging assay to reveal immuno-oncology dynamics as well as the accuracy and efficiency of SiQ-3D to extract quantitative data from large 3D image datasets. SiQ-3D is Python-based, publicly available, and customizable to analyze data from both in vitro and in vivo 3D imaging. The DL-based 3D imaging analysis pipeline can be employed to study not only tumor interaction dynamics with diverse cell types in the TME but also various cell-cell interactions involved in other tissue/organ physiology and pathology. SIGNIFICANCE: A 3D single-cell imaging pipeline that quantifies cancer cell interaction dynamics with other TME cell types using primary patient-derived samples can elucidate how cell-cell interactions impact tumor behavior and treatment responses.

Semi-synthesis and structure-activity relationship study yield antibacterial vicenistatin derivatives with low cytotoxicity.

Vicenistatin (1) is a 20-membered polyketide macrocyclic antibiotic with potent antimicrobial and cytotoxic activities. In this study, to further explore the potential of 1 as candidates of antibacterial drug development, 4'-N-demethyl vicenistatin (2), a secondary metabolite obtained from the ∆vicG mutant strain of Monodonata labio-associated Streptomyces parvus SCSIO Mla-L010, was utilized as a starting material for modifications of 4'-amino group of vicenistatin. Six new vicenistatin derivatives (3-8) were semi-synthesized through a concise route of amino modification with various aliphatic and aromatic aldehydes. Our study reveals that the bioactivity of vicenistatin is closely related to amino modification in sugar moiety, which results from the length of alkyl side chain as well as the presence of electron withdrawing/denoting group on the benzene ring. Importantly, compounds 4 with a butyl group and 8 with a 3,5-dihydroxyl-benzyl group at 4'-amino group, respectively, exhibited good antimicrobial activities, with MIC values spanning 0.5-4 µg ml-1 to Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus epidermidis, Micrococcus luteus and Bacillus subtilis, with low cytotoxicity. This research promotes the further exploration of structure-activity relationships of vicenistatin and provides new vicenistatin derivatives for development of future anti-infectious agents with reduced cytotoxicity.

LncRNA TubAR complexes with TUBB4A and TUBA1A to promote microtubule assembly and maintain myelination.

A long-standing hypothesis proposes that certain RNA(s) must exhibit structural roles in microtubule assembly. Here, we identify a long noncoding RNA (TubAR) that is highly expressed in cerebellum and forms RNA-protein complex with TUBB4A and TUBA1A, two tubulins clinically linked to cerebellar and myelination defects. TubAR knockdown in mouse cerebellum causes loss of oligodendrocytes and Purkinje cells, demyelination, and decreased locomotor activity. Biochemically, we establish the roles of TubAR in promoting TUBB4A-TUBA1A heterodimer formation and microtubule assembly. Intriguingly, different from the hypomyelination-causing mutations, the non-hypomyelination-causing mutation TUBB4A-R2G confers gain-of-function for an RNA-independent interaction with TUBA1A. Experimental use of R2G/A mutations restores TUBB4A-TUBA1A heterodimer formation, and rescues the neuronal cell death phenotype caused by TubAR knockdown. Together, we uncover TubAR as the long-elusive structural RNA for microtubule assembly and demonstrate how TubAR mediates microtubule assembly specifically from αß-tubulin heterodimers, which is crucial for maintenance of cerebellar myelination and activity.

Aurora B promotes the CENP-T-CENP-W interaction to guide accurate chromosome segregation in mitosis.

Accurate chromosome segregation in mitosis depends on kinetochores that connect centromeric chromatin to spindle microtubules. Centromeres are captured by individual microtubules via a kinetochore constitutive centromere-associated network (CCAN) during chromosome segregation. CCAN contains 16 subunits, including CENP-W and CENP-T. However, the molecular recognition and mitotic regulation of the CCAN assembly remain elusive. Here, we revealed that CENP-W binds to the histone fold domain and an uncharacterized N-terminal region of CENP-T. Aurora B phosphorylates CENP-W at threonine 60, which enhances the interaction between CENP-W and CENP-T to ensure robust metaphase chromosome alignment and accurate chromosome segregation in mitosis. These findings delineate a conserved signaling cascade that integrates protein phosphorylation with CCAN integrity for the maintenance of genomic stability.

PRMT1 and TDRD3 promote stress granule assembly by rebuilding the protein-RNA interaction network.

Stress granules (SGs) are membrane-less organelles (MLOs) or cytosolic compartments formed upon exposure to environmental cell stress-inducing stimuli. SGs are based on ribonucleoprotein complexes from a set of cytoplasmic proteins and mRNAs, blocked in translation due to stress cell-induced polysome disassembly. Post-translational modifications (PTMs) such as methylation, are involved in SG assembly, with the methylation writer PRMT1 and its reader TDRD3 colocalizing to SGs. However, the role of this writer-reader system in SG assembly remains unclear. Here, we found that PRMT1 methylates SG constituent RNA-binding proteins (RBPs) on their RGG motifs. Besides, we report that TDRD3, as a reader of asymmetric dimethylarginines, enhances RNA binding to recruit additional RNAs and RBPs, lowering the percolation threshold and promoting SG assembly. Our study enriches our understanding of the molecular mechanism of SG formation by elucidating the functions of PRMT1 and TDRD3. We anticipate that our study will provide a new perspective for comprehensively understanding the functions of PTMs in liquid-liquid phase separation driven condensate assembly.

Myeloid PTEN loss affects the therapeutic response by promoting stress granule assembly and impairing phagocytosis by macrophages in breast cancer.

Breast cancer (BRCA) has become the most common type of cancer in women. Improving the therapeutic response remains a challenge. Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is a classic tumour suppressor with emerging new functions discovered in recent years, and myeloid PTEN loss has been reported to impair antitumour immunity. In this study, we revealed a novel mechanism by which myeloid PTEN potentially affects antitumour immunity in BRCA. We detected accelerated stress granule (SG) assembly under oxidative stress in PTEN-deficient bone marrow-derived macrophages (BMDMs) through the EGR1-promoted upregulation of TIAL1 transcription. PI3K/AKT/mTOR (PAM) pathway activation also promoted SG formation. ATP consumption during SG assembly in BMDMs impaired the phagocytic ability of 4T1 cells, potentially contributing to the disruption of antitumour immunity. In a BRCA neoadjuvant cohort, we observed a poorer response in myeloid PTENlow patients with G3BP1 aggregating as SGs in CD68+ cells, a finding that was consistent with the observation in our study that PTEN-deficient macrophages tended to more readily assemble SGs with impaired phagocytosis. Our results revealed the unconventional impact of SGs on BMDMs and might provide new perspectives on drug resistance and therapeutic strategies for the treatment of BRCA patients.

A bivalent inhibitor against TDRD3 to suppress phase separation of methylated G3BP1.

The formation of membrane-less organelles is driven by multivalent weak interactions while mediation of such interactions by small molecules remains an unparalleled challenge. Here, we uncovered a bivalent inhibitor that blocked the recruitment of TDRD3 by the two methylated arginines of G3BP1. Relative to the monovalent inhibitor, this bivalent inhibitor demonstrated an enhanced binding affinity to TDRD3 and capability to suppress the phase separation of methylated G3BP1, TDRD3, and RNAs, and in turn inhibit the stress granule growth in cells. Our result paves a new path to mediate multivalent interactions involved in SG assembly for potential combinational chemotherapy by bivalent inhibitors.

A mitotic NADPH upsurge promotes chromosome segregation and tumour progression in aneuploid cancer cells.

Redox metabolites have been observed to fluctuate through the cell cycle in cancer cells, but the functional impacts of such metabolic oscillations remain unknown. Here, we uncover a mitosis-specific nicotinamide adenine dinucleotide phosphate (NADPH) upsurge that is essential for tumour progression. Specifically, NADPH is produced by glucose 6-phosphate dehydrogenase (G6PD) upon mitotic entry, which neutralizes elevated reactive oxygen species (ROS) and prevents ROS-mediated inactivation of mitotic kinases and chromosome missegregation. Mitotic activation of G6PD depends on the phosphorylation of its co-chaperone protein BAG3 at threonine 285, which results in dissociation of inhibitory BAG3. Blocking BAG3T285 phosphorylation induces tumour suppression. A mitotic NADPH upsurge is present in aneuploid cancer cells with high levels of ROS, while nearly unobservable in near-diploid cancer cells. High BAG3T285 phosphorylation is associated with worse prognosis in a cohort of patients with microsatellite-stable colorectal cancer. Our study reveals that aneuploid cancer cells with high levels of ROS depend on a G6PD-mediated NADPH upsurge in mitosis to protect them from ROS-induced chromosome missegregation.

ICG-Loaded PEG-Modified Black Phosphorus Nanosheets for Fluorescence Imaging-Guided Breast Cancer Therapy.

Indocyanine green (ICG) has been used in various surgical navigation systems and plays an important role in intraoperative imaging diagnosis. However, the poor photostability and unsatisfactory tumor-targeting ability have limited its broad application prospects. In the decades, the construction of a nanodrug delivery system for tumor-targeting diagnosis and therapy has become a research hotspot. Black phosphorus nanosheets (BPNS), as a new kind of biodegradable nanomaterials, have the advantages of high loading capacity, good biocompatibility, tumor targeting, and photothermal effect over other two-dimensional (2D) reported nanomaterials. Herein, ICG-loaded poly(ethylene glycol) (PEG)-modified BPNS (ICG@BPNS-PEG) nanocomposites are constructed to improve the tumor-targeting capacity and guide photothermal therapy through real-time fluorescence imaging. In this study, ICG@BPNS-PEG nanocomposites with a suitable size (240 ± 28 nm) have been successfully constructed. The photostability of ICG@BPNS-PEG nanocomposites surpassed that of free ICG after four on-off cycles of near laser irradiation (NIR). Moreover, ICG@BPNS-PEG nanocomposites have enhanced photothermal conversion ability. The cellular uptake result through flow cytometry showed that ICG@BPNS-PEG nanocomposites could be swallowed easily owing to the suitable size and passive cellular uptake. In addition, the cytotoxicity evaluation of MCF-7, 4T1 breast cancer cells, and healthy RPE cells through the MTT assay demonstrated that ICG@BPNS-PEG nanocomposites have lower cytotoxicity and good cellular compatibility without irradiation. However, the cytotoxicity and live/dead staining proved that ICG@BPNS-PEG nanocomposites have satisfactory photothermal therapeutic effects when irradiated. In the 4T1-bearing mice model, the fluorescence imaging after intravenous injection of nanocomposites showed that ICG@BPNS-PEG nanocomposites have superior passive tumor targeting accumulation through the enhanced permeability and retention (EPR) effect compared with that of free ICG. Also, changes in tumor volume showed a remarkable tumor growth inhibition effect compared with other groups. Moreover, the results of hematoxylin-eosin (H&E) staining of major organs in 4T1-bearing mice also demonstrated that the nanocomposites have good biocompatibility. Therefore, the constructed ICG@BPNS-PEG nanocomposites have substantial potential in breast cancer therapy.

Energy restriction causes metaphase delay and chromosome mis-segregation in cancer cells.

ATP metabolism during mitosis needs to be coordinated with numerous energy-demanding activities, especially in cancer cells whose metabolic pathways are reprogramed to sustain rapid proliferation in a nutrient-deficient environment. Although strategies targeting the energy metabolic pathways have shown therapeutic efficacy in preclinical cancer models, how normal cells and cancer cells differentially respond to energy shortage is unclear. In this study, using time-lapse microscopy, we found that cancer cells displayed unique mitotic phenotypes in a dose-dependent manner upon decreasing ATP (i.e. energy) supply. When reduction in ATP concentration was moderate, chromosome movements in mitosis were barely affected, while the metaphase-anaphase transition was significantly prolonged due to reduced tension between the sister-kinetochores, which delayed the satisfaction of the spindle assembly checkpoint. Further reduction in ATP concentration led to a decreased level of Aurora-B at the centromere, resulting in increased chromosome mis-segregation after metaphase delay. In contrast to cancer cells, ATP restriction in non-transformed cells induced cell cycle arrest in interphase, rather than causing mitotic defects. In addition, data mining of cancer patient database showed a correlation between signatures of energy production and chromosomal instability possibly resulted from mitotic defects. Together, these results reveal that energy restriction induces differential responses in normal and cancer cells, with chromosome mis-segregation only observed in cancer cells. This points to targeting energy metabolism as a potentially cancer-selective therapeutic strategy.

Kinetochore dynein is required for chromosome motion and congression independent of the spindle checkpoint.

During mitosis, the motor molecule cytoplasmic dynein plays key direct and indirect roles in organizing microtubules (MTs) into a functional spindle. At this time, dynein is also recruited to kinetochores, but its role or roles at these organelles remain vague, partly because inhibiting dynein globally disrupts spindle assembly [1-4]. However, dynein can be selectively depleted from kinetochores by disruption of ZW10 [5], and recent studies with this approach conclude that kinetochore-associated dynein (KD) functions to silence the spindle-assembly checkpoint (SAC) [6]. Here we use dynein-antibody microinjection and the RNAi of ZW10 to explore the role of KD in chromosome behavior during mitosis in mammals. We find that depleting or inhibiting KD prevents the rapid poleward motion of attaching kinetochores but not kinetochore fiber (K fiber) formation. However, after kinetochores attach to the spindle, KD is required for stabilizing kinetochore MTs, which it probably does by generating tension on the kinetochore, and in its absence, chromosome congression is defective. Finally, depleting KD reduces the velocity of anaphase chromosome motion by approximately 40%, without affecting the rate of poleward MT flux. Thus, in addition to its role in silencing the SAC, KD is important for forming and stabilizing K fibers and in powering chromosome motion.

Nudel modulates kinetochore association and function of cytoplasmic dynein in M phase.

The microtubule-based motor cytoplasmic dynein/dynactin is a force generator at the kinetochore. It also transports proteins away from kinetochores to spindle poles. Regulation of such diverse functions, however, is poorly understood. We have previously shown that Nudel is critical for dynein-mediated protein transport, whereas mitosin, a kinetochore protein that binds Nudel, is involved in retention of kinetochore dynein/dynactin against microtubule-dependent stripping. Here we demonstrate that Nudel is required for robust localization of dynein/dynactin at the kinetochore. It localizes to kinetochores after nuclear envelope breakdown, depending mostly ( approximately 78%) on mitosin and slightly on dynein/dynactin. Depletion of Nudel by RNA interference (RNAi) or overexpression of its mutant incapable of binding either Lis1 or dynein heavy chain abolishes the kinetochore protein transport and mitotic progression. Similar to mitosin RNAi, Nudel RNAi also leads to increased stripping of kinetochore dynein/dynactin in the presence of microtubules. Taking together, our results suggest a dual role of kinetochore Nudel: it activates dynein-mediated protein transport and, when interacting with both mitosin and dynein, stabilizes kinetochore dynein/dynactin against microtubule-dependent stripping to facilitate the force generation function of the motor.

Nudel functions in membrane traffic mainly through association with Lis1 and cytoplasmic dynein.

Nudel and Lis1 appear to regulate cytoplasmic dynein in neuronal migration and mitosis through direct interactions. However, whether or not they regulate other functions of dynein remains elusive. Herein, overexpression of a Nudel mutant defective in association with either Lis1 or dynein heavy chain is shown to cause dispersions of membranous organelles whose trafficking depends on dynein. In contrast, the wild-type Nudel and the double mutant that binds to neither protein are much less effective. Time-lapse microscopy for lysosomes reveals significant reduction in both frequencies and velocities of their minus end-directed motions in cells expressing the dynein-binding defective mutant, whereas neither the durations of movement nor the plus end-directed motility is considerably altered. Moreover, silencing Nudel expression by RNA interference results in Golgi apparatus fragmentation and cell death. Together, it is concluded that Nudel is critical for dynein motor activity in membrane transport and possibly other cellular activities through interactions with both Lis1 and dynein heavy chain.

Nudel contributes to microtubule anchoring at the mother centriole and is involved in both dynein-dependent and -independent centrosomal protein assembly.

The centrosome is the major microtubule-organizing center in animal cells. Although the cytoplasmic dynein regulator Nudel interacts with centrosomes, its role herein remains unclear. Here, we show that in Cos7 cells Nudel is a mother centriole protein with rapid turnover independent of dynein activity. During centriole duplication, Nudel targets to the new mother centriole later than ninein but earlier than dynactin. Its centrosome localization requires a C-terminal region that is essential for associations with dynein, dynactin, pericentriolar material (PCM)-1, pericentrin, and gamma-tubulin. Overexpression of a mutant Nudel lacking this region, a treatment previously shown to inactivate dynein, dislocates centrosomal Lis1, dynactin, and PCM-1, with little influence on pericentrin and gamma-tubulin in Cos7 and HeLa cells. Silencing Nudel in HeLa cells markedly decreases centrosomal targeting of all the aforementioned proteins. Silencing Nudel also represses centrosomal MT nucleation and anchoring. Furthermore, Nudel can interact with pericentrin independently of dynein. Our current results suggest that Nudel plays a role in both dynein-mediated centripetal transport of dynactin, Lis1, and PCM-1 as well as in dynein-independent centrosomal targeting of pericentrin and gamma-tubulin. Moreover, Nudel seems to tether dynactin and dynein to the mother centriole for MT anchoring.

Aurora A Inhibition Eliminates Myeloid Cell-Mediated Immunosuppression and Enhances the Efficacy of Anti-PD-L1 Therapy in Breast Cancer.

The Aurora A inhibitor alisertib shows encouraging activities in clinical trials against advanced breast cancer. However, it remains unclear whether and how the inflammatory microenvironment is involved in its efficacy. Here, we demonstrated that inhibition of Aurora A directly reshaped the immune microenvironment through removal of tumor-promoting myeloid cells and enrichment of anticancer T lymphocytes, which established a tumor-suppressive microenvironment and significantly contributed to the regression of murine mammary tumors. Mechanistically, alisertib treatment triggered apoptosis in myeloid-derived suppressor cells (MDSC) and macrophages, resulting in their elimination from tumors. Furthermore, alisertib treatment disrupted the immunosuppressive functions of MDSC by inhibiting Stat3-mediated ROS production. These alterations led to significant increases of active CD8+ and CD4+ T lymphocytes, which efficiently inhibited the proliferation of tumor cells. Intriguingly, alisertib combined with PD-L1 blockade showed synergistic efficacy in the treatment of mammary tumors. These results detail the effects of Aurora A inhibition on the immune microenvironment and provide a novel chemo-immunotherapy strategy for advanced breast cancers. SIGNIFICANCE: These findings show that inhibition of Aurora A facilitates an anticancer immune microenvironment, which can suppress tumor progression and enhance anti-PD-L1 therapy in breast cancer.See related commentary by Rivoltini et al., p. 3169.